In the formation of color paper it is known that the base paper has applied thereto a layer of polymer, typically polyethylene. This layer serves to provide waterproofing to the paper, as well as providing a smooth surface on which the photosensitive layers are formed. The formation of a suitably smooth surface is difficult requiring great care and expense to ensure proper lay down and cooling of the polyethylene layers. The formation of a suitably smooth surface would improve image quality as the display material would have more apparent blackness as the reflective properties of the improved base are more specular than the prior materials. As the whites are whiter and the blacks are blacker, there is more range in between and, therefore, contrast is enhanced. It would be desirable if a more reliable and smoother surface could be formed at less expense.
Prior art photographic reflective papers are typically coated with silver halide imaging layers that contain a separate layer for the magenta, cyan and yellow layers. The color coupler containing layers are typically separated by gelatin inter layers that provide spacing. The spacing of the color coupler containing layers with gelatin inter layers creates a sense of depth in the image to the observer. This sense of depth adds to the quality of a silver halide image and perceptually differentiates a silver halide image from imaging techniques that are more planar. For example, ink jet images do not typically have separation between the ink drops that make up an ink jet image and thus ink jet images appear flat and some what lifeless compared to the same image created from silver halide imaging layers.
It has been found that by increasing the thickness of the gelatin inter layers that the depth of image for a silver halide image can be improved. However, increasing the thickness of the gelatin inter layers reduces the efficiency of the image development process and increases the cost of the imaging material. Also, by increasing the thickness of the gelatin inter layer, the yellowness of the imaging layers causes the density minimum areas to appear more yellow which is undesirable as consumers perceptually prefer density minimum areas that have a slight blue tint.
Prior art stereo photography or depth photography uses visual simulation to provide photographs that can be seen in three dimensions. A stereo camera has two lens placed about 65 mm apart, which is the average interpupillary distance for adults. Two photographs are taken simultaneously of the subject. A stereo viewer is used to present the photograph taken by the left lens to the left eye simultaneously with the one taken by the right lens to the right eye. The human brain then fuses the images into a single image and a three dimensional image of the original subject is seen.
It has been proposed in U.S. Pat. No. 5,866,282 Bourdelais et al. to utilize a composite support material with laminated biaxially oriented polyolefin sheets as a photographic imaging material. In U.S. Pat. No. 5,866,282 biaxially oriented polyolefin sheets are extrusion lamrtinated to cellulose paper to create a support for silver halide imaging layers. The biaxially oriented sheets described in U.S. Pat. No. 5,866,282 have a microvoided layer in combination with coextruded layers that contain white pigments. The composite imaging support structure described in U.S. Pat. No. 5,866,282 has been found to be more durable, sharper and brighter than prior art photographic paper imaging supports that use cast melt extruded polyethylene layers coated on cellulose paper.
Typically, photographic reflective imaging layers are coated on a polyethylene coated cellulose paper. While polyethylene coated cellulose paper does provide an acceptable support for the imaging layers, there is a need for alternate support materials such as polyester or fabric. The problem with alternate, non paper supports is the lack of robustness in photographic processing equipment to mechanical property changes in supports. The photographic processing equipment will not run photographic materials that have significantly different mechanical properties than prior art photographic materials. It would be desirable if a reflective photographic image could be efficiently formed on alternate supports.
The continuing thrust towards digital printing of photographic color papers has created the need for color imaging materials that can work in both a negative working optical and digital exposure equipment. In order for color silver halide imaging materials to correctly print digitally, a color negative curve shape of the imaging material is critical. In a digital environment (direct writing) to a photographic paper, the curve shape to a degree can be electomodulated and thus have a greater degree of freedom that the optical printing of the color negative working system. Ideally, a color paper type imaging system that could substantially maintain tone scale from conventional optical negative working exposure times to sub microsecond digital direct writing exposure times would be preferred. This would enable a photofinishing area to maintain one material for both digital and optical exposure thereby reducing the need for expensive inventory.